Salt Marsh Foraminifera, St. Catherines Island, Georgia: Ecology, Taphonomy, Paleoecology

北美东北部的盐沼和沼泽有孔虫组合与墨西哥湾的盐沼和沼泽有孔虫组合明显不同，但它们之间关键的动物群转换--特别是美国东南海岸特有的沼泽组合--基本上仍未得到研究。同样，这些沉积物中有孔虫测试的损失、保存或重新分布的短期和长期方面在很大程度上仍然未知。本文提出的工作旨在解决这两个问题：东南盐沼有孔虫的生态意义和挖掘学意义。佐治亚州圣凯瑟琳斯岛的现代和残留(-200~1500+年)盐沼沉积物为盐沼有孔虫的埋藏学和古生态研究提供了理想的环境。现代沼泽面积很大，并提供了现代环境的例子，以便与较古老的遗迹沉积物的“古环境”进行比较。沿岛屿东部边缘广泛暴露的残留盐沼沉积物包含保存完好的关键原地特征，这些特征使人们能够识别现代沼泽中所描述的特定盐沼栖息地和子环境。这些沉积物中含有丰富的有孔虫和其他微体化石。因此，利用与现代沼泽研究基本相同的方法，可以实现对这些残留沉积物的有孔虫分布的研究。这项研究的目的是记录和比较圣凯瑟琳现代和残留沼泽沉积物中有孔虫的分布模式。成果将涉及生物地理学、生态学、古生态学、古环境解释，特别是对岩溶和岩溶相的评估。

Salt marshes and marsh foraminiferal assemblages of northeastern North America differ appreciably from those of the Gulf of Mexico, yet the crucial faunal transitions between them-- especially marsh assemblages characteristic of the southeastern U.S. coast--remain essentially unstudied. Similarly, short- and long-term aspects of loss, preservation, or redistribution of foraminiferal tests in these sediments remains largely unknown. The work proposed herein is designed to address both problems: the ecologic and taphonomic significance of southeastern salt marsh foraminifera. Modern and relict (-200 to 1500+ year old) salt marsh sediments of St. Catherines Island, Georgia, provide and ideal setting for studies on the taphonomy and paleoecology of salt marsh foraminifera. Modern marshes are extensive and provide examples of modern environments for comparisons with the "paleoenvironments" of the older relict deposits. Relict salt marsh sediments, extensively exposed along the eastern margin of the island, contain key, well-preserved, in situ features that permit the identification of those specific salt marsh habitats and subenvironments that have been described in modern marshes. Foraminifera and other microfossils are abundant in these deposits. A distributional study on foraminifera of these relict deposits therefore can be achieved utilizing essentially the same methods applicable to studies on modern marshes. The purpose of this study is to document and compare distributional patterns of foraminifera in modern and relict marsh sediments of St. Catherines. Results will address problems of biogeography, ecology, paleoecology, paleoenvironmental interpretations, and particularly the assessment of taphonomy and taphofacies.